A cylinder rod constituting a hydraulic cylinder has its outer peripheral surface serving as a sliding surface. The outer peripheral surface of the cylinder rod is thus desired to have excellent sliding characteristics, wear resistance, etc. To meet such desires, a technique of applying chromium plating to the outer peripheral surface of a cylinder rod has been known (see, for example, Japanese Patent Application Laid-Open No. 2005-105313 (Patent Literature 1) and Japanese Patent Application Laid-Open No. 2006-97875 (Patent Literature 2)).